Threads 101
By Chuck Allison, June 01, 2001
Using multiple threads can make your programs more responsive and your code cleaner, but getting them to work correctly can be tricky. Java makes the task (pun intended) as easy as possible and is the first language to offer portable threading support.
Java Solutions June 2001/import java.*/Listing 11
import java.io.*;
class Counter implements Runnable
{
private int count = 0;
private boolean cancelled = false;
public void run()
{
for (;;) // Loop must not be synchronized!
{
synchronized(this)
{
System.out.println(count++);
if (cancelled)
break;
}
try
{
Thread.sleep(1000);
}
catch (InterruptedException x){}
}
System.out.println("Counter Finished");
}
public synchronized void cancel()
{
cancelled = true;
}
}
class Cancel3
{
public static void main(String[] args)
{
System.out.println("Press Enter to Cancel:");
Counter c = new Counter();
new Thread(c).start();
try
{
System.in.read();
}
catch (IOException x)
{
System.out.println(x);
}
c.cancel(); // Don't forget this!
System.out.println("Exiting main");
}
}
/* Output:
Press Enter to Cancel:
0
1
Exiting main
2
Counter Finished
*/
— End of Listing —
